MediaWIKI 1.31 + mwlib

[takenek]

Hello Guys,
I have got a problem with MediaWIKI and mwlib, when i generate PDF and open this pdf file i get inside information:
"WARNING: Article could not be rendered - ouputting plain text.
Potential causes of the problem are: (a) a bug in the pdf-writer software (b) problematic Mediawiki markup (c) table

i use MediaWIKI 1.31.1 with Collection extension 1.7.0.
Os is Debian 9 with: Python 2.7.13 and this python module:
root@WIKI:/usr/local/lib/python2.7/dist-packages# ls -al
drwxrwsr-x 14 root staff 4096 mar 8 2017 .
drwxrwsr-x 4 root staff 4096 wrz 30 11:24 ..
drwxr-sr-x 3 root staff 4096 mar 8 2017 apipkg-1.4-py2.7.egg
drwxr-sr-x 3 root staff 4096 mar 8 2017 bottle-0.12.13-py2.7.egg
-rw-r--r-- 1 root staff 522 mar 8 2017 easy-install.pth
drwxr-sr-x 4 root staff 4096 mar 8 2017 gevent-1.2.1-py2.7-linux-x86_64.egg
drwxr-sr-x 3 root staff 4096 mar 8 2017 greenlet-0.4.12-py2.7-linux-x86_64.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 mwlib-0.15.14-py2.7-linux-x86_64.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 mwlib.ext-0.13.2-py2.7-linux-x86_64.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 mwlib.rl-0.14.5-py2.7.egg
-rw-r--r-- 1 root root 267918 mar 8 2017 odfpy-0.9.6-py2.7.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 py-1.4.32-py2.7.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 Pygments-2.2.0-py2.7.egg
drwxr-sr-x 3 root staff 4096 mar 8 2017 pyparsing-1.5.7-py2.7.egg
-rw-r--r-- 1 root root 70070 mar 8 2017 pyPdf-1.13-py2.7.egg
-rw-r--r-- 1 root root 29923 mar 8 2017 qserve-0.2.8-py2.7.egg
-rw-r--r-- 1 root root 4053 mar 8 2017 roman-2.0.0-py2.7.egg
drwxr-sr-x 4 root staff 4096 mar 8 2017 simplejson-3.10.0-py2.7-linux-x86_64.egg
-rw-r--r-- 1 root root 17818 mar 8 2017 sqlite3dbm-0.1.4-py2.7.egg
drwxr-sr-x 3 root staff 4096 mar 8 2017 timelib-0.2.4-py2.7-linux-x86_64.egg

Anyone can help me?
Best Regards